Damage to carbon nanotubes (CNTs) during the fabrication process of CNT reinforced composites has great influence on their mechanical properties. In this study, the 2014 Al with powder sizes of 20, 9 and 5 μm was selected to study the effect of initial particle size on the damage to carbon nanotubes (CNTs) during ball milling. The result shows that for CNTs in the ball milled CNT/Al (with powder size of 20 and 9 μm) mixtures, the intensity ratio of the D band and the G band (ID/IG) first increased and then reached a plateau, mainly because most of the CNTs are embedded, to a certain extent, in the aluminum powder after milling, which could protect the CNTs from damage during further milling. While for CNTs in the ball milled CNT/Al (with powder size of 5 μm) mixture, the ID/IG ratio continues to climb from 1.31 to 2.33 with time, indicating continuous damage to the CNTs occurs during the milling. Differential scanning calorimetry (DSC) analysis demonstrates that the chemical instability increased with an increase in the damage level of CNTs, resulting in the formation of aluminum carbide (Al₄C₃) at a lower temperature before the melting of aluminum, which is detrimental to their mechanical properties.

A structurally integrated design scheme with vertical interconnection is proposed to address the structural design requirements of low profile and severe thermal conditions encountered at the front end of phased-array antennas for high-speed aircraft. By applying low-frequency and radio-frequency fuzz buttons, board-level cable-free vertical interconnection is achieved, with an antenna profile height of less than 35 mm. Through targeted measures such as structurally integrated design and thermal-insulation tile design, along with simulation analysis, the environmental adaptability challenges caused by high heat flux density at the front end of the phased-array antenna are resolved. This provides a reference for the structural design of similar phased array antenna front ends.